A definition is presented for high‐speed memories, and the spectrum of uses ranging from extended main memories to buffers is examined. An analysis is made of factors influencing total cost and performance of both magnetic and semiconductor memories in terms of drive requirements, array costs, failure rate, access time, propagation delay, connections, packaging, power consumption, modularity, debugging ease, and integrated circuit compatibility. Fundamental economic and performance factors such as cell density, batch size, cell complexity and power dissipation also are examined to highlight future potential development in each area. In addition, business factors such as second source availability, industry commitment, general technical under‐, standing and training requirements are considered. Finally, a projection is made indicating a growth in both magnetic and semiconductor memories for the next several years with the largest percentage growth in semiconductor memories.